Fan control

Abstract

A method for controlling fan operation that includes detecting a stopped fan and attempting to start the stopped fan. The method includes attempting to start the stopped fan again after at least one first time interval when the fan does not start. The method includes attempting to start the stopped fan again after at least one second time interval when the fan does not start after a predetermined number of first time intervals, where the at least one second time interval is longer than the first time interval.

1. A method for restarting a stopped fan, the method comprising:
 attempting to start the stopped fan while setting at least one other fan at full speed;  
 setting the at least one other fan at a percentage of full speed after attempting to start the stopped fan;  
 attempting to start the stopped fan again after at least one first time interval when the fan does not start; and  
 attempting to start the stopped fan again after at least one second time interval when the fan does not start after a predetermined number of first time intervals, wherein the at least one second time interval is longer than the first time interval.  
 
     
     
       2. The method of  claim 1 , further comprising setting the stopped fan at a percentage of full speed when the stopped fan starts. 
     
     
       3. A method for restarting a stopped fan, the method comprising:
 attempting to start the stopped fan;  
 setting at least one other fan at full speed while attempting to start the stopped fan;  
 setting the at least one other fan at a percentage of the full speed that is less than the full speed after attempting to start the stopped fan;  
 setting the at least one other fan at the full speed again while attempting to start the stopped fan again after waiting at least one first time interval when the stopped fan does not start; and  
 setting the at least one other fan at the full speed again while attempting to start the stopped fan again after waiting at least one second time interval when the stopped fan does not start after a predetermined number of first time intervals, wherein the at least one second time interval is longer than the first time interval.  
 
     
     
       4. The method of  claim 3 , further comprising setting the stopped fan at a percentage of full speed when the stopped fan starts. 
     
     
       5. The method of  claim 4 , wherein setting the stopped fan at a percentage of full speed when the stopped fan starts occurs at a temperature within a predetermined range. 
     
     
       6. The method of  claim 3 , wherein setting the at least one other fan at a percentage of full speed occurs at a temperature within a predetermined range. 
     
     
       7. A method for controlling fan operation, the method comprising:
 detecting a stopped fan;  
 attempting to start the stopped fan;  
 setting at least one other fan at full speed while attempting to start the stopped fan;  
 setting the at least one other fan at a percentage of full speed after attempting to start the stopped fan;  
 attempting to start the stopped fan again after at least one first time interval when the fan does not start; and  
 attempting to start the stopped fan again after at least one second time interval when the fan does not start after a predetermined number of first time intervals, wherein the at least one second time interval is longer than the first time interval.  
 
     
     
       8. The method of  claim 7 , further comprising setting the stopped fan at a percentage of full speed when the stopped fan starts. 
     
     
       9. The method of  claim 7 , further comprising activating an alarm upon detecting the stopped fan. 
     
     
       10. The method of  claim 7 , further comprising deactivating an alarm when the stopped fan starts. 
     
     
       11. A method for controlling fan operation, the method comprising:
 detecting a stopped fan; attempting to start the stopped fan while setting at least one other fan at full speed;  
 setting the at least one other fan at a percentage of the full speed that is less than the full speed after attempting to start the stopped fan;  
 attempting to start the stopped fan again while setting the at least one other fan at the full speed again after at least one first time interval when the stopped fan does not start; and  
 attempting to start the stopped fan again while setting the at least one other fan at the full speed again after at least one second time interval when the stopped fan does not start after a predetermined number of first time intervals, wherein the at least one second time interval is longer than the first time interval.  
 
     
     
       12. The method of  claim 11 , further comprising setting the stopped fan at a percentage of full speed when the stopped fan starts. 
     
     
       13. The method of  claim 12 , wherein setting the stopped fan at a percentage of full speed when the stopped fan starts occurs at a temperature within a predetermined range. 
     
     
       14. The method of  claim 11 , wherein setting the at least one other fan at a percentage of full speed occurs at a temperature within a predetermined range. 
     
     
       15. A method for controlling fan operation, the method comprising:
 detecting a stopped fan;  
 executing a restart method for starting the stopped fan where the restart method includes: 
 attempting to start the stopped fan while setting at least one other fan at full speed;  
 setting the at least one other fan at a percentage of the full speed that is less than the full speed after attempting to start the stopped fan;  
 attempting to start the stopped fan again while setting the at least one other fan at the full speed again after at least one first time interval when the stopped fan does not start; and  
 attempting to start the stopped fan again while setting the at least one other fan at full speed again after at least one second time interval when the stopped fan does not start after a predetermined number of first time intervals, wherein the at least one second time interval is longer than the first time interval;  
 
 terminating the restart method when a shutdown condition occurs;  
 retaining a stopped-fan fault indicative of the stopped fan when the shutdown condition occurs; and  
 executing the restart method for starting the stopped fan when the shutdown condition no longer exists.  
 
     
     
       16. A method for controlling fan operation, the method comprising:
 detecting a stopped fan;  
 shutting off power to the stopped fan at a temperature corresponding to a freezing temperature of a lubricant of the stopped fan;  
 retaining a stopped-fan fault indicative of the stopped fan when the power is shut off;  
 restoring power to the stopped fan at a temperature greater than the freezing temperature of the lubricant; and  
 executing a restart method for starting the stopped fan.  
 
     
     
       17. A machine-readable medium comprising machine-usable instructions for causing a circuit card to perform a method of controlling fan operation, the method comprising:
 detecting a stopped fan;  
 attempting to start the stopped fan while setting at least one other fan at full speed;  
 setting the at least one other fan at a percentage of full speed after attempting to start the stopped fan;  
 attempting to start the stopped fan again after at least one first time interval when the fan does not start; and  
 attempting to start the stopped fan again after at least one second time interval when the fan does not start after a predetermined number of first time intervals, wherein the at least one second time interval is longer than the first time interval.  
 
     
     
       18. The method of  claim 17 , further comprising setting the stopped fan at a percentage of full speed when the stopped fan starts. 
     
     
       19. The method of  claim 17 , further comprising activating an alarm upon detecting the stopped fan. 
     
     
       20. The method of  claim 17 , further comprising deactivating an alarm when the stopped fan starts. 
     
     
       21. A machine-readable medium comprising machine-usable instructions for causing a circuit card to perform a method of restarting a stopped fan, the method comprising:
 attempting to start the stopped fan while setting at least one other fan at full speed;  
 setting the at least one other fan at a percentage of full speed after attempting to start the stopped fan;  
 attempting to start the stopped fan again after at least one first time interval when the fan does not start; and  
 attempting to start the stopped fan again after at least one second time interval when the fan does not start after a predetermined number of first time intervals, wherein the at least one second time interval is longer than the first time interval.  
 
     
     
       22. The method of  claim 21 , further comprising setting the stopped fan at a percentage of full speed when the stopped fan starts. 
     
     
       23. A machine-readable medium comprising machine-usable instructions for causing a circuit card to perform a method of controlling fan operation, the method comprising:
 detecting a stopped fan;  
 executing a restart method for starting the stopped fan where the restart method includes; 
 attempting to start the stopped fan while setting at least one other fan at full speed;  
 setting the at least one other fan at a percentage of the full speed that is less than the full speed after attempting to start the stopped fan;  
 attempting to start the stopped fan again while setting the at least one other fan at the full speed again after at least one first time interval when the stopped fan does not start; and  
 attempting to start the stopped fan again while setting the at least one other fan at full speed again after at least one second time interval when the stopped fan does not start after a predetermined number of first time intervals, wherein the at least one second time interval is longer than the first time interval;  
 
 terminating the restart method when a shutdown condition occurs;  
 retaining a stopped-fan fault indicative of the stopped fan when the shutdown condition occurs; and  
 executing the restart method for starting the stopped fan when the shutdown condition no longer exists.